This invention relates to a system for retaining a frameless door within a vehicle body.
A typical vehicle includes multiple doors by which passengers can enter and leave the vehicle. Conventionally, vehicle doors include a glass window covering an opening that is bounded by a frame and a housing into which the glass window can be at least partially retracted. In its fully extended position the glass window engages with the frame and covers the opening in the door. Typically the frame will have a seal which stops the ingress of water into the car and shuts out wind noise generated by the motion of the vehicle.
In an alternative configuration found in some modern vehicles, the vehicle door does not feature a frame surrounding the glass window and the glass window is therefore not supported along much of its edge. The seal for the glass window that was provided by the frame of the door is now provided at the vehicle body. In some vehicles, when a frameless door is closed the edge of the window rests against a seal on the vehicle body. The mechanism of the door can be arranged such that the window is pushed into the seal when the door is closed. However such an arrangement does not securely hold the window in place and cannot be safely used in vehicles with a very high top speed which can generate significant differences in pressures between the inside and outside of the vehicle.
A better solution for a frameless door is to arrange for the top edge of the window to fit inside a seal around the door opening in the car body, in analogous fashion to a window in a door with a frame. However, in order to achieve this the window must be retracted slightly into its housing whenever the door is opened so that the top edge of the window is pulled out of the seal prior to the door being opened. When the door is shut the window is pushed into the seal such that its top edge is contained inside the seal. This window movement is generally linked to the door release mechanism, so that the window immediately slides down in response to the user engaging the door release mechanism.
In order to allow such frameless doors to be released in the event of a failure of the vehicle electrics (and hence the window motor), the door must be openable without the window being lowered slightly to release the window from the seal. This ensures that occupants are not trapped inside the vehicle in the event of a crash. Such cars therefore need to have a seal at the top of the window which resists the ingress of water and wind noise into the cabin but which is flexible enough to allow the top edge of the window to be forced out of the seal. However, such a door arrangement is often not strong enough to securely retain the window glass in a vehicle travelling at high speeds, such as can occur in a high performance sports car. At high speeds the air flow over the outside of the car causes a significant pressure difference between the inside and outside of the car, sucking the door windows outwards and potentially out of their seals. Nevertheless, frameless door designs can be aesthetically desirable, particularly in sports cars.
There is therefore a need for an improved frameless door arrangement suitable for a vehicle capable of travelling at high speeds.